Contagious Equine Metritis (CEM) was detected in the Netherlands for the first time in 1987. A total number of five mares (Dutch saddle-horse) were infected in three separate outbreaks. The origin of the infection could not be determined in any of the cases. As the isolates of the causal organism, Taylorella equigenitalis, showed auto-agglutination, diagnosis was difficult. Therefore, an indirect immune fluorescence test as used to diagnose the second isolate. Five strains were isolated, which all were resistant to streptomycin. The prevalence of CEM since 1981 is summarised. The importance of CEM in horse-breeding is discussed.